arch/arc/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   4  *
   5  * vineetg: June 2010
   6  *    -__clear_user( ) called multiple times during elf load was byte loop
   7  *    converted to do as much word clear as possible.
   8  *
   9  * vineetg: Dec 2009
  10  *    -Hand crafted constant propagation for "constant" copy sizes
  11  *    -stock kernel shrunk by 33K at -O3
  12  *
  13  * vineetg: Sept 2009
  14  *    -Added option to (UN)inline copy_(to|from)_user to reduce code sz
  15  *    -kernel shrunk by 200K even at -O3 (gcc 4.2.1)
  16  *    -Enabled when doing -Os
  17  *
  18  * Amit Bhor, Sameer Dhavale: Codito Technologies 2004
  19  */
  20
  21 #ifndef _ASM_ARC_UACCESS_H
  22 #define _ASM_ARC_UACCESS_H
  23
  24 #include <linux/string.h>       /* for generic string functions */
  25
  26
  27 #define __kernel_ok             (uaccess_kernel())
  28
  29 /*
  30  * Algorithmically, for __user_ok() we want do:
  31  *      (start < TASK_SIZE) && (start+len < TASK_SIZE)
  32  * where TASK_SIZE could either be retrieved from thread_info->addr_limit or
  33  * emitted directly in code.
  34  *
  35  * This can however be rewritten as follows:
  36  *      (len <= TASK_SIZE) && (start+len < TASK_SIZE)
  37  *
  38  * Because it essentially checks if buffer end is within limit and @len is
  39  * non-ngeative, which implies that buffer start will be within limit too.
  40  *
  41  * The reason for rewriting being, for majority of cases, @len is generally
  42  * compile time constant, causing first sub-expression to be compile time
  43  * subsumed.
  44  *
  45  * The second part would generate weird large LIMMs e.g. (0x6000_0000 - 0x10),
  46  * so we check for TASK_SIZE using get_fs() since the addr_limit load from mem
  47  * would already have been done at this call site for __kernel_ok()
  48  *
  49  */
  50 #define __user_ok(addr, sz)     (((sz) <= TASK_SIZE) && \
  51                                  ((addr) <= (get_fs() - (sz))))
  52 #define __access_ok(addr, sz)   (unlikely(__kernel_ok) || \
  53                                  likely(__user_ok((addr), (sz))))
  54
  55 /*********** Single byte/hword/word copies ******************/
  56
  57 #define __get_user_fn(sz, u, k)                                 \
  58 ({                                                              \
  59         long __ret = 0; /* success by default */        \
  60         switch (sz) {                                           \
  61         case 1: __arc_get_user_one(*(k), u, "ldb", __ret); break;       \
  62         case 2: __arc_get_user_one(*(k), u, "ldw", __ret); break;       \
  63         case 4: __arc_get_user_one(*(k), u, "ld", __ret);  break;       \
  64         case 8: __arc_get_user_one_64(*(k), u, __ret);     break;       \
  65         }                                                       \
  66         __ret;                                                  \
  67 })
  68
  69 /*
  70  * Returns 0 on success, -EFAULT if not.
  71  * @ret already contains 0 - given that errors will be less likely
  72  * (hence +r asm constraint below).
  73  * In case of error, fixup code will make it -EFAULT
  74  */
  75 #define __arc_get_user_one(dst, src, op, ret)   \
  76         __asm__ __volatile__(                   \
  77         "1:     "op"    %1,[%2]\n"              \
  78         "2:     ;nop\n"                         \
  79         "       .section .fixup, \"ax\"\n"      \
  80         "       .align 4\n"                     \
  81         "3:     # return -EFAULT\n"             \
  82         "       mov %0, %3\n"                   \
  83         "       # zero out dst ptr\n"           \
  84         "       mov %1,  0\n"                   \
  85         "       j   2b\n"                       \
  86         "       .previous\n"                    \
  87         "       .section __ex_table, \"a\"\n"   \
  88         "       .align 4\n"                     \
  89         "       .word 1b,3b\n"                  \
  90         "       .previous\n"                    \
  91                                                 \
  92         : "+r" (ret), "=r" (dst)                \
  93         : "r" (src), "ir" (-EFAULT))
  94
  95 #define __arc_get_user_one_64(dst, src, ret)    \
  96         __asm__ __volatile__(                   \
  97         "1:     ld   %1,[%2]\n"                 \
  98         "4:     ld  %R1,[%2, 4]\n"              \
  99         "2:     ;nop\n"                         \
 100         "       .section .fixup, \"ax\"\n"      \
 101         "       .align 4\n"                     \
 102         "3:     # return -EFAULT\n"             \
 103         "       mov %0, %3\n"                   \
 104         "       # zero out dst ptr\n"           \
 105         "       mov %1,  0\n"                   \
 106         "       mov %R1, 0\n"                   \
 107         "       j   2b\n"                       \
 108         "       .previous\n"                    \
 109         "       .section __ex_table, \"a\"\n"   \
 110         "       .align 4\n"                     \
 111         "       .word 1b,3b\n"                  \
 112         "       .word 4b,3b\n"                  \
 113         "       .previous\n"                    \
 114                                                 \
 115         : "+r" (ret), "=r" (dst)                \
 116         : "r" (src), "ir" (-EFAULT))
 117
 118 #define __put_user_fn(sz, u, k)                                 \
 119 ({                                                              \
 120         long __ret = 0; /* success by default */        \
 121         switch (sz) {                                           \
 122         case 1: __arc_put_user_one(*(k), u, "stb", __ret); break;       \
 123         case 2: __arc_put_user_one(*(k), u, "stw", __ret); break;       \
 124         case 4: __arc_put_user_one(*(k), u, "st", __ret);  break;       \
 125         case 8: __arc_put_user_one_64(*(k), u, __ret);     break;       \
 126         }                                                       \
 127         __ret;                                                  \
 128 })
 129
 130 #define __arc_put_user_one(src, dst, op, ret)   \
 131         __asm__ __volatile__(                   \
 132         "1:     "op"    %1,[%2]\n"              \
 133         "2:     ;nop\n"                         \
 134         "       .section .fixup, \"ax\"\n"      \
 135         "       .align 4\n"                     \
 136         "3:     mov %0, %3\n"                   \
 137         "       j   2b\n"                       \
 138         "       .previous\n"                    \
 139         "       .section __ex_table, \"a\"\n"   \
 140         "       .align 4\n"                     \
 141         "       .word 1b,3b\n"                  \
 142         "       .previous\n"                    \
 143                                                 \
 144         : "+r" (ret)                            \
 145         : "r" (src), "r" (dst), "ir" (-EFAULT))
 146
 147 #define __arc_put_user_one_64(src, dst, ret)    \
 148         __asm__ __volatile__(                   \
 149         "1:     st   %1,[%2]\n"                 \
 150         "4:     st  %R1,[%2, 4]\n"              \
 151         "2:     ;nop\n"                         \
 152         "       .section .fixup, \"ax\"\n"      \
 153         "       .align 4\n"                     \
 154         "3:     mov %0, %3\n"                   \
 155         "       j   2b\n"                       \
 156         "       .previous\n"                    \
 157         "       .section __ex_table, \"a\"\n"   \
 158         "       .align 4\n"                     \
 159         "       .word 1b,3b\n"                  \
 160         "       .word 4b,3b\n"                  \
 161         "       .previous\n"                    \
 162                                                 \
 163         : "+r" (ret)                            \
 164         : "r" (src), "r" (dst), "ir" (-EFAULT))
 165
 166
 167 static inline unsigned long
 168 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 169 {
 170         long res = 0;
 171         char val;
 172         unsigned long tmp1, tmp2, tmp3, tmp4;
 173         unsigned long orig_n = n;
 174
 175         if (n == 0)
 176                 return 0;
 177
 178         /* unaligned */
 179         if (((unsigned long)to & 0x3) || ((unsigned long)from & 0x3)) {
 180
 181                 unsigned char tmp;
 182
 183                 __asm__ __volatile__ (
 184                 "       mov.f   lp_count, %0            \n"
 185                 "       lpnz 2f                         \n"
 186                 "1:     ldb.ab  %1, [%3, 1]             \n"
 187                 "       stb.ab  %1, [%2, 1]             \n"
 188                 "       sub     %0,%0,1                 \n"
 189                 "2:     ;nop                            \n"
 190                 "       .section .fixup, \"ax\"         \n"
 191                 "       .align 4                        \n"
 192                 "3:     j   2b                          \n"
 193                 "       .previous                       \n"
 194                 "       .section __ex_table, \"a\"      \n"
 195                 "       .align 4                        \n"
 196                 "       .word   1b, 3b                  \n"
 197                 "       .previous                       \n"
 198
 199                 : "+r" (n),
 200                 /*
 201                  * Note as an '&' earlyclobber operand to make sure the
 202                  * temporary register inside the loop is not the same as
 203                  *  FROM or TO.
 204                 */
 205                   "=&r" (tmp), "+r" (to), "+r" (from)
 206                 :
 207                 : "lp_count", "memory");
 208
 209                 return n;
 210         }
 211
 212         /*
 213          * Hand-crafted constant propagation to reduce code sz of the
 214          * laddered copy 16x,8,4,2,1
 215          */
 216         if (__builtin_constant_p(orig_n)) {
 217                 res = orig_n;
 218
 219                 if (orig_n / 16) {
 220                         orig_n = orig_n % 16;
 221
 222                         __asm__ __volatile__(
 223                         "       lsr   lp_count, %7,4            \n"
 224                         "       lp    3f                        \n"
 225                         "1:     ld.ab   %3, [%2, 4]             \n"
 226                         "11:    ld.ab   %4, [%2, 4]             \n"
 227                         "12:    ld.ab   %5, [%2, 4]             \n"
 228                         "13:    ld.ab   %6, [%2, 4]             \n"
 229                         "       st.ab   %3, [%1, 4]             \n"
 230                         "       st.ab   %4, [%1, 4]             \n"
 231                         "       st.ab   %5, [%1, 4]             \n"
 232                         "       st.ab   %6, [%1, 4]             \n"
 233                         "       sub     %0,%0,16                \n"
 234                         "3:     ;nop                            \n"
 235                         "       .section .fixup, \"ax\"         \n"
 236                         "       .align 4                        \n"
 237                         "4:     j   3b                          \n"
 238                         "       .previous                       \n"
 239                         "       .section __ex_table, \"a\"      \n"
 240                         "       .align 4                        \n"
 241                         "       .word   1b, 4b                  \n"
 242                         "       .word   11b,4b                  \n"
 243                         "       .word   12b,4b                  \n"
 244                         "       .word   13b,4b                  \n"
 245                         "       .previous                       \n"
 246                         : "+r" (res), "+r"(to), "+r"(from),
 247                           "=r"(tmp1), "=r"(tmp2), "=r"(tmp3), "=r"(tmp4)
 248                         : "ir"(n)
 249                         : "lp_count", "memory");
 250                 }
 251                 if (orig_n / 8) {
 252                         orig_n = orig_n % 8;
 253
 254                         __asm__ __volatile__(
 255                         "14:    ld.ab   %3, [%2,4]              \n"
 256                         "15:    ld.ab   %4, [%2,4]              \n"
 257                         "       st.ab   %3, [%1,4]              \n"
 258                         "       st.ab   %4, [%1,4]              \n"
 259                         "       sub     %0,%0,8                 \n"
 260                         "31:    ;nop                            \n"
 261                         "       .section .fixup, \"ax\"         \n"
 262                         "       .align 4                        \n"
 263                         "4:     j   31b                         \n"
 264                         "       .previous                       \n"
 265                         "       .section __ex_table, \"a\"      \n"
 266                         "       .align 4                        \n"
 267                         "       .word   14b,4b                  \n"
 268                         "       .word   15b,4b                  \n"
 269                         "       .previous                       \n"
 270                         : "+r" (res), "+r"(to), "+r"(from),
 271                           "=r"(tmp1), "=r"(tmp2)
 272                         :
 273                         : "memory");
 274                 }
 275                 if (orig_n / 4) {
 276                         orig_n = orig_n % 4;
 277
 278                         __asm__ __volatile__(
 279                         "16:    ld.ab   %3, [%2,4]              \n"
 280                         "       st.ab   %3, [%1,4]              \n"
 281                         "       sub     %0,%0,4                 \n"
 282                         "32:    ;nop                            \n"
 283                         "       .section .fixup, \"ax\"         \n"
 284                         "       .align 4                        \n"
 285                         "4:     j   32b                         \n"
 286                         "       .previous                       \n"
 287                         "       .section __ex_table, \"a\"      \n"
 288                         "       .align 4                        \n"
 289                         "       .word   16b,4b                  \n"
 290                         "       .previous                       \n"
 291                         : "+r" (res), "+r"(to), "+r"(from), "=r"(tmp1)
 292                         :
 293                         : "memory");
 294                 }
 295                 if (orig_n / 2) {
 296                         orig_n = orig_n % 2;
 297
 298                         __asm__ __volatile__(
 299                         "17:    ldw.ab   %3, [%2,2]             \n"
 300                         "       stw.ab   %3, [%1,2]             \n"
 301                         "       sub      %0,%0,2                \n"
 302                         "33:    ;nop                            \n"
 303                         "       .section .fixup, \"ax\"         \n"
 304                         "       .align 4                        \n"
 305                         "4:     j   33b                         \n"
 306                         "       .previous                       \n"
 307                         "       .section __ex_table, \"a\"      \n"
 308                         "       .align 4                        \n"
 309                         "       .word   17b,4b                  \n"
 310                         "       .previous                       \n"
 311                         : "+r" (res), "+r"(to), "+r"(from), "=r"(tmp1)
 312                         :
 313                         : "memory");
 314                 }
 315                 if (orig_n & 1) {
 316                         __asm__ __volatile__(
 317                         "18:    ldb.ab   %3, [%2,2]             \n"
 318                         "       stb.ab   %3, [%1,2]             \n"
 319                         "       sub      %0,%0,1                \n"
 320                         "34:    ; nop                           \n"
 321                         "       .section .fixup, \"ax\"         \n"
 322                         "       .align 4                        \n"
 323                         "4:     j   34b                         \n"
 324                         "       .previous                       \n"
 325                         "       .section __ex_table, \"a\"      \n"
 326                         "       .align 4                        \n"
 327                         "       .word   18b,4b                  \n"
 328                         "       .previous                       \n"
 329                         : "+r" (res), "+r"(to), "+r"(from), "=r"(tmp1)
 330                         :
 331                         : "memory");
 332                 }
 333         } else {  /* n is NOT constant, so laddered copy of 16x,8,4,2,1  */
 334
 335                 __asm__ __volatile__(
 336                 "       mov %0,%3                       \n"
 337                 "       lsr.f   lp_count, %3,4          \n"  /* 16x bytes */
 338                 "       lpnz    3f                      \n"
 339                 "1:     ld.ab   %5, [%2, 4]             \n"
 340                 "11:    ld.ab   %6, [%2, 4]             \n"
 341                 "12:    ld.ab   %7, [%2, 4]             \n"
 342                 "13:    ld.ab   %8, [%2, 4]             \n"
 343                 "       st.ab   %5, [%1, 4]             \n"
 344                 "       st.ab   %6, [%1, 4]             \n"
 345                 "       st.ab   %7, [%1, 4]             \n"
 346                 "       st.ab   %8, [%1, 4]             \n"
 347                 "       sub     %0,%0,16                \n"
 348                 "3:     and.f   %3,%3,0xf               \n"  /* stragglers */
 349                 "       bz      34f                     \n"
 350                 "       bbit0   %3,3,31f                \n"  /* 8 bytes left */
 351                 "14:    ld.ab   %5, [%2,4]              \n"
 352                 "15:    ld.ab   %6, [%2,4]              \n"
 353                 "       st.ab   %5, [%1,4]              \n"
 354                 "       st.ab   %6, [%1,4]              \n"
 355                 "       sub.f   %0,%0,8                 \n"
 356                 "31:    bbit0   %3,2,32f                \n"  /* 4 bytes left */
 357                 "16:    ld.ab   %5, [%2,4]              \n"
 358                 "       st.ab   %5, [%1,4]              \n"
 359                 "       sub.f   %0,%0,4                 \n"
 360                 "32:    bbit0   %3,1,33f                \n"  /* 2 bytes left */
 361                 "17:    ldw.ab  %5, [%2,2]              \n"
 362                 "       stw.ab  %5, [%1,2]              \n"
 363                 "       sub.f   %0,%0,2                 \n"
 364                 "33:    bbit0   %3,0,34f                \n"
 365                 "18:    ldb.ab  %5, [%2,1]              \n"  /* 1 byte left */
 366                 "       stb.ab  %5, [%1,1]              \n"
 367                 "       sub.f   %0,%0,1                 \n"
 368                 "34:    ;nop                            \n"
 369                 "       .section .fixup, \"ax\"         \n"
 370                 "       .align 4                        \n"
 371                 "4:     j   34b                         \n"
 372                 "       .previous                       \n"
 373                 "       .section __ex_table, \"a\"      \n"
 374                 "       .align 4                        \n"
 375                 "       .word   1b, 4b                  \n"
 376                 "       .word   11b,4b                  \n"
 377                 "       .word   12b,4b                  \n"
 378                 "       .word   13b,4b                  \n"
 379                 "       .word   14b,4b                  \n"
 380                 "       .word   15b,4b                  \n"
 381                 "       .word   16b,4b                  \n"
 382                 "       .word   17b,4b                  \n"
 383                 "       .word   18b,4b                  \n"
 384                 "       .previous                       \n"
 385                 : "=r" (res), "+r"(to), "+r"(from), "+r"(n), "=r"(val),
 386                   "=r"(tmp1), "=r"(tmp2), "=r"(tmp3), "=r"(tmp4)
 387                 :
 388                 : "lp_count", "memory");
 389         }
 390
 391         return res;
 392 }
 393
 394 static inline unsigned long
 395 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 396 {
 397         long res = 0;
 398         char val;
 399         unsigned long tmp1, tmp2, tmp3, tmp4;
 400         unsigned long orig_n = n;
 401
 402         if (n == 0)
 403                 return 0;
 404
 405         /* unaligned */
 406         if (((unsigned long)to & 0x3) || ((unsigned long)from & 0x3)) {
 407
 408                 unsigned char tmp;
 409
 410                 __asm__ __volatile__(
 411                 "       mov.f   lp_count, %0            \n"
 412                 "       lpnz 3f                         \n"
 413                 "       ldb.ab  %1, [%3, 1]             \n"
 414                 "1:     stb.ab  %1, [%2, 1]             \n"
 415                 "       sub     %0, %0, 1               \n"
 416                 "3:     ;nop                            \n"
 417                 "       .section .fixup, \"ax\"         \n"
 418                 "       .align 4                        \n"
 419                 "4:     j   3b                          \n"
 420                 "       .previous                       \n"
 421                 "       .section __ex_table, \"a\"      \n"
 422                 "       .align 4                        \n"
 423                 "       .word   1b, 4b                  \n"
 424                 "       .previous                       \n"
 425
 426                 : "+r" (n),
 427                 /* Note as an '&' earlyclobber operand to make sure the
 428                  * temporary register inside the loop is not the same as
 429                  * FROM or TO.
 430                  */
 431                   "=&r" (tmp), "+r" (to), "+r" (from)
 432                 :
 433                 : "lp_count", "memory");
 434
 435                 return n;
 436         }
 437
 438         if (__builtin_constant_p(orig_n)) {
 439                 res = orig_n;
 440
 441                 if (orig_n / 16) {
 442                         orig_n = orig_n % 16;
 443
 444                         __asm__ __volatile__(
 445                         "       lsr lp_count, %7,4              \n"
 446                         "       lp  3f                          \n"
 447                         "       ld.ab %3, [%2, 4]               \n"
 448                         "       ld.ab %4, [%2, 4]               \n"
 449                         "       ld.ab %5, [%2, 4]               \n"
 450                         "       ld.ab %6, [%2, 4]               \n"
 451                         "1:     st.ab %3, [%1, 4]               \n"
 452                         "11:    st.ab %4, [%1, 4]               \n"
 453                         "12:    st.ab %5, [%1, 4]               \n"
 454                         "13:    st.ab %6, [%1, 4]               \n"
 455                         "       sub   %0, %0, 16                \n"
 456                         "3:;nop                                 \n"
 457                         "       .section .fixup, \"ax\"         \n"
 458                         "       .align 4                        \n"
 459                         "4:     j   3b                          \n"
 460                         "       .previous                       \n"
 461                         "       .section __ex_table, \"a\"      \n"
 462                         "       .align 4                        \n"
 463                         "       .word   1b, 4b                  \n"
 464                         "       .word   11b,4b                  \n"
 465                         "       .word   12b,4b                  \n"
 466                         "       .word   13b,4b                  \n"
 467                         "       .previous                       \n"
 468                         : "+r" (res), "+r"(to), "+r"(from),
 469                           "=r"(tmp1), "=r"(tmp2), "=r"(tmp3), "=r"(tmp4)
 470                         : "ir"(n)
 471                         : "lp_count", "memory");
 472                 }
 473                 if (orig_n / 8) {
 474                         orig_n = orig_n % 8;
 475
 476                         __asm__ __volatile__(
 477                         "       ld.ab   %3, [%2,4]              \n"
 478                         "       ld.ab   %4, [%2,4]              \n"
 479                         "14:    st.ab   %3, [%1,4]              \n"
 480                         "15:    st.ab   %4, [%1,4]              \n"
 481                         "       sub     %0, %0, 8               \n"
 482                         "31:;nop                                \n"
 483                         "       .section .fixup, \"ax\"         \n"
 484                         "       .align 4                        \n"
 485                         "4:     j   31b                         \n"
 486                         "       .previous                       \n"
 487                         "       .section __ex_table, \"a\"      \n"
 488                         "       .align 4                        \n"
 489                         "       .word   14b,4b                  \n"
 490                         "       .word   15b,4b                  \n"
 491                         "       .previous                       \n"
 492                         : "+r" (res), "+r"(to), "+r"(from),
 493                           "=r"(tmp1), "=r"(tmp2)
 494                         :
 495                         : "memory");
 496                 }
 497                 if (orig_n / 4) {
 498                         orig_n = orig_n % 4;
 499
 500                         __asm__ __volatile__(
 501                         "       ld.ab   %3, [%2,4]              \n"
 502                         "16:    st.ab   %3, [%1,4]              \n"
 503                         "       sub     %0, %0, 4               \n"
 504                         "32:;nop                                \n"
 505                         "       .section .fixup, \"ax\"         \n"
 506                         "       .align 4                        \n"
 507                         "4:     j   32b                         \n"
 508                         "       .previous                       \n"
 509                         "       .section __ex_table, \"a\"      \n"
 510                         "       .align 4                        \n"
 511                         "       .word   16b,4b                  \n"
 512                         "       .previous                       \n"
 513                         : "+r" (res), "+r"(to), "+r"(from), "=r"(tmp1)
 514                         :
 515                         : "memory");
 516                 }
 517                 if (orig_n / 2) {
 518                         orig_n = orig_n % 2;
 519
 520                         __asm__ __volatile__(
 521                         "       ldw.ab    %3, [%2,2]            \n"
 522                         "17:    stw.ab    %3, [%1,2]            \n"
 523                         "       sub       %0, %0, 2             \n"
 524                         "33:;nop                                \n"
 525                         "       .section .fixup, \"ax\"         \n"
 526                         "       .align 4                        \n"
 527                         "4:     j   33b                         \n"
 528                         "       .previous                       \n"
 529                         "       .section __ex_table, \"a\"      \n"
 530                         "       .align 4                        \n"
 531                         "       .word   17b,4b                  \n"
 532                         "       .previous                       \n"
 533                         : "+r" (res), "+r"(to), "+r"(from), "=r"(tmp1)
 534                         :
 535                         : "memory");
 536                 }
 537                 if (orig_n & 1) {
 538                         __asm__ __volatile__(
 539                         "       ldb.ab  %3, [%2,1]              \n"
 540                         "18:    stb.ab  %3, [%1,1]              \n"
 541                         "       sub     %0, %0, 1               \n"
 542                         "34:    ;nop                            \n"
 543                         "       .section .fixup, \"ax\"         \n"
 544                         "       .align 4                        \n"
 545                         "4:     j   34b                         \n"
 546                         "       .previous                       \n"
 547                         "       .section __ex_table, \"a\"      \n"
 548                         "       .align 4                        \n"
 549                         "       .word   18b,4b                  \n"
 550                         "       .previous                       \n"
 551                         : "+r" (res), "+r"(to), "+r"(from), "=r"(tmp1)
 552                         :
 553                         : "memory");
 554                 }
 555         } else {  /* n is NOT constant, so laddered copy of 16x,8,4,2,1  */
 556
 557                 __asm__ __volatile__(
 558                 "       mov   %0,%3                     \n"
 559                 "       lsr.f lp_count, %3,4            \n"  /* 16x bytes */
 560                 "       lpnz  3f                        \n"
 561                 "       ld.ab %5, [%2, 4]               \n"
 562                 "       ld.ab %6, [%2, 4]               \n"
 563                 "       ld.ab %7, [%2, 4]               \n"
 564                 "       ld.ab %8, [%2, 4]               \n"
 565                 "1:     st.ab %5, [%1, 4]               \n"
 566                 "11:    st.ab %6, [%1, 4]               \n"
 567                 "12:    st.ab %7, [%1, 4]               \n"
 568                 "13:    st.ab %8, [%1, 4]               \n"
 569                 "       sub   %0, %0, 16                \n"
 570                 "3:     and.f %3,%3,0xf                 \n" /* stragglers */
 571                 "       bz 34f                          \n"
 572                 "       bbit0   %3,3,31f                \n" /* 8 bytes left */
 573                 "       ld.ab   %5, [%2,4]              \n"
 574                 "       ld.ab   %6, [%2,4]              \n"
 575                 "14:    st.ab   %5, [%1,4]              \n"
 576                 "15:    st.ab   %6, [%1,4]              \n"
 577                 "       sub.f   %0, %0, 8               \n"
 578                 "31:    bbit0   %3,2,32f                \n"  /* 4 bytes left */
 579                 "       ld.ab   %5, [%2,4]              \n"
 580                 "16:    st.ab   %5, [%1,4]              \n"
 581                 "       sub.f   %0, %0, 4               \n"
 582                 "32:    bbit0 %3,1,33f                  \n"  /* 2 bytes left */
 583                 "       ldw.ab    %5, [%2,2]            \n"
 584                 "17:    stw.ab    %5, [%1,2]            \n"
 585                 "       sub.f %0, %0, 2                 \n"
 586                 "33:    bbit0 %3,0,34f                  \n"
 587                 "       ldb.ab    %5, [%2,1]            \n"  /* 1 byte left */
 588                 "18:    stb.ab  %5, [%1,1]              \n"
 589                 "       sub.f %0, %0, 1                 \n"
 590                 "34:    ;nop                            \n"
 591                 "       .section .fixup, \"ax\"         \n"
 592                 "       .align 4                        \n"
 593                 "4:     j   34b                         \n"
 594                 "       .previous                       \n"
 595                 "       .section __ex_table, \"a\"      \n"
 596                 "       .align 4                        \n"
 597                 "       .word   1b, 4b                  \n"
 598                 "       .word   11b,4b                  \n"
 599                 "       .word   12b,4b                  \n"
 600                 "       .word   13b,4b                  \n"
 601                 "       .word   14b,4b                  \n"
 602                 "       .word   15b,4b                  \n"
 603                 "       .word   16b,4b                  \n"
 604                 "       .word   17b,4b                  \n"
 605                 "       .word   18b,4b                  \n"
 606                 "       .previous                       \n"
 607                 : "=r" (res), "+r"(to), "+r"(from), "+r"(n), "=r"(val),
 608                   "=r"(tmp1), "=r"(tmp2), "=r"(tmp3), "=r"(tmp4)
 609                 :
 610                 : "lp_count", "memory");
 611         }
 612
 613         return res;
 614 }
 615
 616 static inline unsigned long __arc_clear_user(void __user *to, unsigned long n)
 617 {
 618         long res = n;
 619         unsigned char *d_char = to;
 620
 621         __asm__ __volatile__(
 622         "       bbit0   %0, 0, 1f               \n"
 623         "75:    stb.ab  %2, [%0,1]              \n"
 624         "       sub %1, %1, 1                   \n"
 625         "1:     bbit0   %0, 1, 2f               \n"
 626         "76:    stw.ab  %2, [%0,2]              \n"
 627         "       sub %1, %1, 2                   \n"
 628         "2:     asr.f   lp_count, %1, 2         \n"
 629         "       lpnz    3f                      \n"
 630         "77:    st.ab   %2, [%0,4]              \n"
 631         "       sub %1, %1, 4                   \n"
 632         "3:     bbit0   %1, 1, 4f               \n"
 633         "78:    stw.ab  %2, [%0,2]              \n"
 634         "       sub %1, %1, 2                   \n"
 635         "4:     bbit0   %1, 0, 5f               \n"
 636         "79:    stb.ab  %2, [%0,1]              \n"
 637         "       sub %1, %1, 1                   \n"
 638         "5:                                     \n"
 639         "       .section .fixup, \"ax\"         \n"
 640         "       .align 4                        \n"
 641         "3:     j   5b                          \n"
 642         "       .previous                       \n"
 643         "       .section __ex_table, \"a\"      \n"
 644         "       .align 4                        \n"
 645         "       .word   75b, 3b                 \n"
 646         "       .word   76b, 3b                 \n"
 647         "       .word   77b, 3b                 \n"
 648         "       .word   78b, 3b                 \n"
 649         "       .word   79b, 3b                 \n"
 650         "       .previous                       \n"
 651         : "+r"(d_char), "+r"(res)
 652         : "i"(0)
 653         : "lp_count", "memory");
 654
 655         return res;
 656 }
 657
 658 #ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
 659
 660 #define INLINE_COPY_TO_USER
 661 #define INLINE_COPY_FROM_USER
 662
 663 #define __clear_user(d, n)              __arc_clear_user(d, n)
 664 #else
 665 extern unsigned long arc_clear_user_noinline(void __user *to,
 666                 unsigned long n);
 667 #define __clear_user(d, n)              arc_clear_user_noinline(d, n)
 668 #endif
 669
 670 #include <asm/segment.h>
 671 #include <asm-generic/uaccess.h>
 672
 673 #endif